插入排序

特点：原址排序，比较排序，（最坏的情况）时间复杂度O（n^2）

#include <iostream>void insertion_sort(int *arr,int start,int end)
{for (int i = start+1; i < end+1; ++i) {int key = arr[i];int j = i-1;while (j>=start && key<arr[j]){arr[j+1] = arr[j];j--;}arr[j+1] = key;}
}
void show(int *arr,int length)
{for(int i=0;i<length;i++){std::cout<<arr[i]<<" ";}std::cout<<std::endl;
}int main()
{int arr[] = {1,4,6,9,2,5,10,3,7};show(arr,sizeof(arr)/sizeof (int));insertion_sort(arr,0,sizeof(arr)/sizeof (int)-1);show(arr,sizeof(arr)/sizeof (int));return 0;
}

嵌入递归的插入排序
T(n) = T(n) + n-1
(最坏的情况）时间复杂度O（n^2）

void recursion_insertion_sort(int *arr,int start,int end)
{if(start<end){recursion_insertion_sort(arr,start,end-1);int pos = end - 1;int key = arr[end];while (pos >= start && key < arr[pos]){arr[pos+1] = arr[pos];pos--;}arr[pos+1] = key;}
}